How to implement After Advice using @AspectJ Annotation-Driven AOP in Java ?.

A simple application to demonstrate how to implement After Advice using @AspectJ Annotation-Driven AOP in Java.

Step 1:- Create a Interface Sum.java

package com.hubberspot.aspectj.annotation.afteradvice;
// Its a simple interface for the Sum service.
// It contains one single method called as addition().
// This method takes in two arguments both of the type
// int.
public interface Sum {
public int addition(int a , int b);
}

Step 2:- SumImpl.java Service Implementation Class

package com.hubberspot.aspectj.annotation.afteradvice;
// It is the implementation class for the
// Sum service. It just calculates and returns
// sum of two numbers passed to it as arguments.
public class SumImpl implements Sum {
@Override
public int addition(int a, int b) {
System.out.println("Addition method called ...");
return (a + b);
}
}

package com.hubberspot.aspectj.annotation.afteradvice;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class SumTest {
public static void main(String[] args) {
// ApplicationContext is a Spring interface which
// provides with the configuration for an application.
// It provides us with all the methods that BeanFactory
// provides. It loads the file resources in a older
// and generic manner. It helps us to publish events to the
// listener registered to it. It also provides quick support
// for internationalization. It provides us with the object
// requested, it reads the configuration file and provides
// us with the necessary object required.
// We are using concrete implementation of AbstractApplicationContext
// here called as ClassPathXmlApplicationContext because this
// bean factory reads the xml file placed in the classpath of
// our application. We provide ClassPathXmlApplicationContext
// with a configuration file called as before_advice.xml placed
// at classpath of our application.
ApplicationContext context =
new ClassPathXmlApplicationContext("after_advice.xml");
// In order to get a object instantiated for a particular bean
// we call getBean() method of ClassPathXmlApplicationContext
// passing it the id for which the object is to be needed.
// Here getBean() returns an Object. We need to cast it back
// to the Sum object. Without implementing new keyword we
// have injected object of Sum just by reading an xml
// configuration file.
Sum sum = (Sum)context.getBean("sum");
int result = sum.addition(5, 10);
System.out.println("Result = " + result);
}
}

Output of the program :

A simple application to demonstrate how to implement After Advice using @AspectJ Annotation-Driven AOP in Java.

Step 1:- Create a Interface Sum.java

package com.hubberspot.aspectj.annotation.afteradvice;
// Its a simple interface for the Sum service.
// It contains one single method called as addition().
// This method takes in two arguments both of the type
// int.
public interface Sum {
public int addition(int a , int b);
}

Step 2:- SumImpl.java Service Implementation Class

package com.hubberspot.aspectj.annotation.afteradvice;
// It is the implementation class for the
// Sum service. It just calculates and returns
// sum of two numbers passed to it as arguments.
public class SumImpl implements Sum {
@Override
public int addition(int a, int b) {
System.out.println("Addition method called ...");
return (a + b);
}
}

package com.hubberspot.aspectj.annotation.afteradvice;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class SumTest {
public static void main(String[] args) {
// ApplicationContext is a Spring interface which
// provides with the configuration for an application.
// It provides us with all the methods that BeanFactory
// provides. It loads the file resources in a older
// and generic manner. It helps us to publish events to the
// listener registered to it. It also provides quick support
// for internationalization. It provides us with the object
// requested, it reads the configuration file and provides
// us with the necessary object required.
// We are using concrete implementation of AbstractApplicationContext
// here called as ClassPathXmlApplicationContext because this
// bean factory reads the xml file placed in the classpath of
// our application. We provide ClassPathXmlApplicationContext
// with a configuration file called as before_advice.xml placed
// at classpath of our application.
ApplicationContext context =
new ClassPathXmlApplicationContext("after_advice.xml");
// In order to get a object instantiated for a particular bean
// we call getBean() method of ClassPathXmlApplicationContext
// passing it the id for which the object is to be needed.
// Here getBean() returns an Object. We need to cast it back
// to the Sum object. Without implementing new keyword we
// have injected object of Sum just by reading an xml
// configuration file.
Sum sum = (Sum)context.getBean("sum");
int result = sum.addition(5, 10);
System.out.println("Result = " + result);
}
}